1. Technical Field
Embodiments disclosed herein are related to a multi-spot laser probe having a micro-structured faceted proximal surface and methods for manufacturing the same. In particular, some embodiments disclosed herein provide a multi-spot laser probe having a micro-structured faceted proximal surface and a micro-structured distal surface and method for manufacturing the same that may reduce a total internal reflectance back into the laser probe.
2. Related Art
Laser probes may deliver light to multiple spots onto a surgical target. For example, in the course of pan-retinal photocoagulation of retinal tissue, delivering light to multiple spots can reduce the time of the surgical procedure. In existing system various techniques have been employed to produce multiple beams for a multi-spot pattern. For example, one approach uses diffractive elements at the distal end of the probe to divide an incoming beam into multiple beams.
Difficulties, however, can arise with using diffractive elements at the distal end of the probe. For example, diffractive elements can produce a multitude of higher diffraction orders and thus a large number of additional, unwanted, extraneous beam spots that will irradiate the retina. These additional spots, in spite of having lower intensities, may have negative effects, such as undesirable heating of the target region. Moreover, a diffractive element may not perform the same in different refractive media. For example, a diffractive element may be placed into a medium with a different refractive index than that of air, and spaces between the diffractive elements may fill with the medium, which may affect the spot pattern. Furthermore, the spacing between the spots can vary for different wavelengths, which can cause problems if an aiming beam and a treatment beam are different colors. Diffractive elements are also frequently expensive and difficult to produce, especially if the diffractive element is to fit into a small area.
Some laser probes utilize a single fiber to guide the light from a light source to a ball lens. The ball lens can be immersed into a cured, optically transmissive adhesive with multiple facets to split the light beam. However, both the proximal and the distal surfaces of the cured adhesive reflect as much as 5% of the incident light back into the laser probe, causing problems related to overheating such as material degradation of the adhesive.
Accordingly, there is a need for a multi-spot laser probe that (a) can provide multiple spots at a surgical target without overheating the probe, (b) without the problems associated with diffractive elements, and (c) that can be fabricated at an acceptable cost.